The present invention relates to an exterior rearview mirror for mounting on a vehicle and, more particularly, to an extendable exterior rearview mirror for mounting on a vehicle which can be extended to a position spaced farther outboard and away from the vehicle body than the normal mirror viewing position when the vehicle is used for towing a trailer, camper, another vehicle, or the like.
Conventional towing mirrors include a mirror subassembly that is mounted to the body of a vehicle by a support and mounting bracket. The support positions the mirror subassembly at a fixed distance from the body of the vehicle which is farther than the position of conventional exterior rearview mirrors in order to provide an unobstructed view to the rear of the towed object. For example, U.S. Pat. No. 3,119,591 to A. J. Malecki discloses a rigid support for eccentrically mounting a mirror assembly to a vehicle in a fixed extended position. Naturally, these fixed extended rearview mirror assemblies increase the width of the vehicle. In some vehicles, the width is increased beyond the maximum width allowed by conventional vehicle transport trucks which deliver the vehicles to the dealership. Therefore, these mirror assemblies are typically installed at the dealership, which ultimately increases the cost of the vehicle.
In addition, use of the prior known fixed, extended rearview mirror assemblies is also inconvenient for the driver who only occasionally tows a trailer. Since such mirror assemblies substantially increase the width of the vehicle, they hamper normal maneuvering through passages, such as those defined by garage door openings, drive through banking structures, and the like. Furthermore, they are more vulnerable to being damaged or causing damage than conventional exterior rearview mirrors, especially when used by an inexperienced driver. This inconvenience is compounded by the fact that, not only do these extended rearview mirrors generally detract from the appearance of the vehicle, they increase the cost of the vehicle.
In response to the needs of the drivers who only occasionally tow objects, several extendible mirror assemblies have been developed. For example, in U.S. Pat. Nos. 5,513,048 and 5,489,080, each disclose mirrors supported on telescoping tubular members which are fixed in position by threaded fasteners. Though simple in construction, these telescoping members typically require the operator to use a tool to adjust the position of the mirror. Moreover, they tend to increase the vibration of the mirror assembly, which may in turn loosen the connection between the telescoping members of the mirror assembly, especially when the mirror assembly is in the outboard position.
In U.S. Pat. No. 5,546,239 to Lewis, an extendable mirror element is disclosed in which the mirror element is extended from the mirror casing to an outboard position. Again, the mounting bracketry lacks the structure to perform well in vibration. Furthermore, the mirror element is more vulnerable to damage.
In contrast, U.S. Pat. No. 5,572,376 to Pace discloses an extensible vehicle mirror which includes a rack and pinion drive system and drive motor to translate a mirror longitudinally along the mirror support arm. As a result, Pace's mirror assembly is relatively complicated and the associated parts increase the weight of the mirror assembly significantly. The more parts that require assembling, the greater the costs of manufacture. Moreover, weight increases of this magnitude tend to increase the vibration of the mirror assembly and degrade the performance of the mirror.
Consequently, there is a need for an extendable exterior rearview mirror that can be installed at the factory, which provides the extended field of view required when towing vehicles and yet can be manually retracted to a normal operating position where it does not hamper the maneuverability of the vehicle. Moreover, the extendable rearview mirror should have minimal impact on the vibration of the mirror assembly and be relatively easy to adjust between non-towing and towing positions without the need for tools.